Guy Foucart

Assessment of energy crops alternative to maize for biogas production in the Greater Region

The biomethane yield of various energy crops, selected among potential alternatives to maize in the Greater Region, was assessed. The biomass yield, the volatile solids (VS) content and the biochemical methane potential (BMP) were measured to calculate the biomethane yield per hectare of all plant species. For all species, the dry matter biomass yield and the VS content were the main factors that influence, respectively, the biomethane yield and the BMP. Both values were predicted with good accuracy by linear regressions using the biomass yield and the VS as independent variable. The perennial crop miscanthus appeared to be the most promising alternative to maize when harvested as green matter in autumn and ensiled. Miscanthus reached a biomethane yield of 5.5 ± 1 × 10(3)m(3)ha(-1) during the second year after the establishment, as compared to 5.3 ± 1 × 10(3)m(3)ha(-1) for maize under similar crop conditions.

Biodiversity of Fusarium species in ears and stalks of maize plants in Belgium

In order to investigate the pre-harvest contamination of maize plants by Fusarium species in Belgium, a three-year survey has been performed in five fields in which three hybrids differing in susceptibility to maize stalk rot were sampled at four different physiological stages. An extensive collection of 5,659 Fusarium isolates characterized at the species level was established during the 2005, 2006, and 2007 growing seasons, with a total of 23 different Fusarium species identified to occur on ears and stalks. A high number of plants was already contaminated by Fusarium spp. at the anthesis stage, although no symptoms were visible on ears or on stalks. As the season progressed, the incidence of Fusarium-infected maize plants reached 100% in several fields. At the end of the growing season, the most frequently isolated species in maize ears were F. graminearum, sometimes associated with F. avenaceum, F. crookwellense, F. culmorum, F. poae, and F. temperatum, a new species recently described on maize. The predominant Fusarium species detected in stalks at the end of the growing season were F. graminearum and F. crookwellense, often associated with F. culmorum and F. temperatum. Year-to-year variability observed for the incidence of F. graminearum can most likely be associated with differences in climatic conditions among the three years.

Assessment of factors influencing the biomethane yield of maize silages

A large set of maize silage samples was produced to assess the major traits influencing the biomethane production of this crop. The biomass yield, the volatile solids contents and the biochemical methane potential (BMP) were measured to calculate the biomethane yield per hectare (average=7266m(3)ha(-1)). The most influential factor controlling the biomethane yield was the cropping environment. The biomass yield had more impact than the anaerobic digestibility. Nevertheless, the anaerobic digestibility of maize silages was negatively affected by high VS content in mature maize. Late maturing maize varieties produced high biomass yield with high digestibility resulting in high biomethane yield per hectare. The BMP was predicted with good accuracy using solely the VS content.

Fusarium miscanthi and other Fusarium species as causal agents of Miscanthus × giganteus rhizome rot

In 2010, Miscanthus × giganteus rhizomes were collected from Belgian fields showing emergence reduction and were analyzed for detection and identification of fungal species. All rhizomes were infected by at least one Fusarium species, of which F. culmorum, F. miscanthi, F. crookwellense and F. graminearum were the most abundant. Results of the pathogenicity tests by soil inoculation demonstrate the ability of F. miscanthi, F. culmorum and F. avenaceum to cause rhizome rot disease under greenhouse conditions. This is the first report of F. miscanthi and other Fusarium species isolated from M. × giganteus rhizomes in Belgium.